If I ferment cold do I have to wait a lot longer for the dough to rise?
You do have to wait longer as fermentation rate is quite dependant on temperature.
An excellent experiment to illustrate the effects of cold fermentation would be to mix up a large batch of your typical dough. At the stage where you ball up your dough, split the dough into 3 sets of balls.
Set 1: Do what you normally do.
Set 2: place balls in lightly oiled glad containers place in fridge for 2 days. Take out 3 hours prior to baking.
Set 3: Do the same thing as step 2 but age in fridge for 4 days.
I think you'll find the flavor change interesting.
Again wild yeast will amplify this flavor change.